
s1_read_last_two_bytes_of_a_mbr_backup_file(){
local file_path=$1
local last_bytes=$(tail -c 2 "$file_path" | od -A n -t x1 | tr -d ' \n')
if [ "$last_bytes" = "55aa" ];then
     echo "YES"
else
     echo "NO"
fi
}
s2_read_mbr_partition_table_info(){
    for i in {0..3}; do
          offset=$((446 + i * 16))
          start_sector=$(dd if="$1" bs=1 skip=$((offset + 8)) count=4 2>/dev/null | od -t u4 -An |tr -d'\n')
          if ![[$start_sector =~^[0-9]+$ ]];then
               continue
          fi
          if [ "$start_sector" -eq 0 ];then
               continue
          fi
          size_sector=$(dd if="$1" bs= 1 skip=$((offset + 12)) count=4 2>/dev/null | od -t u4 -An | tr -d '\n')
          end_sector=$((start_sector + size_sector - 1))
          echo "$start_sector $end_sector"
     done
}
s3_parse_partition_info(){
    fdisk_output=$(cat)
    disk_size_bytes=$(echo "$fdike_output" | greo "Disk /dev/vda:" | awk '{print $5}')
    disk_size_sectors=$(echo "$fdisk_output" | greo "Disk /dev/vda:" |awk '{print $7}')
    physical_sector_size=$(echo "$fdisk_output" | grep "Sector size" | awk '{print $3}')
    first_partition_start_sector=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{orint $3}')
    first_partition_end_sector=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $4}')
    first_partition_type=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $8}')
echo "disk size in bytes:$disk_size_bytes"
echo "disk size in sectors:$disk_size_sectors"
echo "physical sector size in bytes:$physical_sector_size"
echo "first partition end sector id:$first_partition_end_sector"
echo "first partition type:$first_partition_type"
}
s4_run_passwd_as_plain_user_and_get_status(){
oversleeping_path=$(which oversleeping)
chown root "$oversleeping_path"
chmod 4755 "$oversleeping_path"
oversleeping &
ps -o uid,euid,ruid -C oversleeping | awk 'NR>1 {print $1","$2","$3"}'
}
a5_add_a_scheduled_task(){
touch $HOME/test_crontab;
echo "*/5 * * * * date +\%Y\%M\%d_\%H\%M\%S >> $HOME/test_crontab" | crontab -
}
